New breast cancer gene discovered

Researchers may have found the key to unlocking the genetic code behind a host of serious diseases, following the discovery of a new breast cancer gene mutation.

A large international study led by University of Melbourne researchers has identified a mutation linked to breast cancer attached to the newly identified gene, called XRCC2.

Lead researcher Melissa Southey said the discovery, using high-speed technology, would hopefully mean that more gene mutations responsible for causing breast cancer could be rapidly identified in the next few years.

Currently, people with a history of breast cancer in their family can only be screened for two of the disease's known genetic mutations, Prof Southey said.

The two genes account for about 20 per cent of breast cancer cases, she said, with the remaining 80 per cent not linked to any known mutations, she said.

"At the moment, if a woman with a strong family history of breast cancer goes to clinical genetic services and undergoes testing for the genes that we know today, the most likely outcome is that she will not be found to have a mutation in any of those genes," Prof Southey told AAP.

Prof Southey said the study, published on Friday in the American Journal of Human Genetics, was continuing, with much more data to analyse.

"We really are very optimistic that we will find additional genes like this."

Prof Southey said researchers used the latest genetic sequencing technology, called massively parallel sequencing, in the discovery.

Previously DNA sequencing using a method called Sanger sequencing could take weeks or months, she said.

By using the new method scientists could analyse a person's entire DNA in a few days, Prof Southey said.

Initially, the XRCC2 mutation was found in two families by Prof Southey and a colleague based in The Netherlands.

The discovery formed the basis for a much larger study to determine whether the mutation was more widely responsible for breast cancer, which proved correct.

The DNA of 689 families with multiple members affected by breast cancer, and 1308 women who had early onset breast cancer, was then analysed, as well as 1120 healthy people.

One of the study's co-authors, Melbourne University's Dr Daniel Park, said the findings showed the technology could be used to discover other cancer-causing genes.

"Our study approach could be applied to many other common, complex diseases with components of unexplained heritability, such as colorectal and prostate cancers," he said in a statement.